DESCRIPTION OF THE DIGITAL DATABASE FOR 

 Geologic Map of MTM -15027, -20027, -25027, and -25032 Quadrangles, Margaritifer Terra Region of Mars

 USGS SCIENTIFIC INVESTIGATIONS MAP 3209

 ISSN 2329-132X (online)

ISSN 2329-1311 (print)

DOI http://dx.doi.org/10.3133/sim3209

 Reference: Irwin, Rossman P., III, and John A. Grant, 2013, Geologic Map of MTM -15027, -20027, 

 -25027, and -25032 Quadrangles, Margaritifer Terra Region of Mars, U.S. Geological Survey 

 Scientific Investigations Map 3209, scale 1:1,000,000. Available at http://pubs.usgs.gov/sim/3209/

 INTRODUCTION

 Mars Transverse Mercator (MTM) quadrangles -15027, -20027, -25027, and -25032 (lat 12.5°-28° S., 

 long 330°-335° E. and lat 22.5°-28° S., long 324.5°-330° E.) in southwestern Margaritifer Terra include 

 diverse erosional landforms, sedimentary deposits, and tectonic structures that record a long 

 geologic and geomorphic history. The northeastern regional slope of the pre-Noachian crustal dichotomy 

 (as expressed along the Chryse trough) and structures of the informally named Middle Noachian or older 

 Holden and Ladon impact basins dominate the topography of the map area. A series of mesoscale outflow 

 channels, Uzboi, Ladon, and Morava Valles, integrated these formerly enclosed basins by overflow and 

 incision around the Noachian/Hesperian transition, although some flooding may have occurred earlier. 

 The area includes excellent examples of Late Noachian to Hesperian valley networks, dissected crater 

 rims, alluvial fans, deltas, and light-toned layered deposits (LTLDs), particularly in Holden and 

 Eberswalde craters. Structural forms include Tharsis-radial grabens, Hesperian wrinkle ridges, 

 floor-fractured impact craters, and severely disrupted chaotic terrains. These well-preserved 

 landforms and sedimentary deposits represent multiple erosional epochs and discrete flooding events, 

 which provide significant insight into the geomorphic processes and climate change on early Mars.

 

 All GIS data are in Transverse_Mercator projection using the

 Mars 2000 geographic coordinate system

 (GCS_Mars_2000). Units are in meters.

 GEOLOGIC CONTENT (contents of "Vector" Folder,

 SIM3209_geodatabase.gdb)

 This ArcGIS geodatabase contains one feature dataset

 (SIM3209_feature_dataset) with the following features:

 SIM3209_contacts - Line feature class, geologic unit and map

 boundaries including symbol types: Approximate, certain.

 SIM3209_label_points - Point feature class, center point locations of

 geologic units.

 

 SIM3209_nomenclature - Annotation feature class, contains

 the names approved by the International Astronomical Union Working

 Group for Planetary System Nomenclature.

 SIM3209_Geology - Polygon feature class, geologic unit polygon

 feature class. Contains a "Unit_type" field denoting the unit symbol.

 SIM3209_structure - Line feature class, denoting structural features.

 SIM3209_impact_basin_rings - line feature class denoting impact

 basin rings.

 BASE MAP CONTENT

The U.S. Geological Survey provided the 231 m/pixel base map derived 

from the Viking Mars Digital Image Mosaic 2.1. The base uses a Transverse 

Mercator projection, the Mars Orbiter Laser Altimeter (MOLA) 2000 datum, 

and a central meridian of 330 E. We made an equivalent base mosaic using 

Mars Odyssey Thermal Emission Imaging System (THEMIS) daytime infrared (DIR) 

imaging at 100 m/pixel (fig. 2), and we reprojected and georeferenced part 

of the Arizona State University THEMIS nighttime infrared mosaic 2.0 at 

231 m/pixel as an overlay (fig. 3). Detailed mapping was based on THEMIS 

visible images at 18 m/pixel and Mars Reconnaissance Orbiter (MRO) Context 

Camera images at 5 m/pixel (not included). Where available, Mars Orbiter 

Camera (MOC) images at ~2-5 m/pixel, MRO High Resolution Imaging Science

Experiment (HiRISE) visible images at 25 cm/pixel, and Compact Reconnaissance

Imaging Spectrometer for Mars (CRISM) products facilitated local 

interpretations of within-unit 2 stratigraphy (not included). Topographic 

measurements were based on the 128 pixel/degree MOLA Mission Experiment 

Gridded Data Record (not included).

 DIGITAL DATABASE AND METADATA PACKAGE (SIM3209_database.zip)

 The geologic map files, basemaps, and supportive files are included

 in the database package, as described below:
 "SIM_3209" directory

 --------------------------------------------

 Files Description

 ---------------------------------------------------------------------

 ---------------------------------------------------------------------

 SIM3209_README.txt This readme file.

 SIM3209_metadata.txt Text-format FGDC-style metadata for the

 database package

 SIM3209_metadata.xml XML-format FGDC-style metadata for the

 database package

 SIM3209_ArcMap10.mxd ArcGIS (version 10) project for the database package

 "Base_maps" directory

 --------------------------------------------

 SIM3209_basemap_THEMIS_IRday.tif - THEMIS daytime mosaic produced by authors

 SIM3209_THEMIS_IRnight.tif - THEMIS daytime mosaic produced by Arizona State Univ.

 SIM3209_Viking_MDIM21.tif - Viking MDIM 2.1 produced by USGS

 "Vector" directory

 --------------------------------------------

 "SIM3209_geodatabase.gdb" - ArcMap 9.3 versioned geodatabase

 "Shapefiles" -

 This directory contains GIS shapefiles exported from the ArcGIS

 geodatabase described above. As such, the names and descriptions for

 each shapefile are identical to the content of the included

 geodatabase. See above "GEOLOGIC CONTENT" for details.

 Users of the database package may wish to download the PDF version

 of the map for the Description of Map Units.

 The material described above is available on the World Wide Web at

 http:/pubs.usgs.gov/sim/3209/.

 ZIP FILES

 The files described above are packaged within a ZIP file. Utilities

 to uncompress ZIP files are available for most operating systems and

 may be found readily with a simple web search.

 DIGITAL DATABASE FORMAT

 The digital information compiled in this report used v 10, a

 commercial Geographic Information System produced by Environmental

 Systems Research Institute, Redlands, California.

 OBTAINING HARD-COPY OF SIM 3209

 USGS Information Services

 Box 25286

 Denver Federal Center

 Denver, CO 80225-0046

 (303) 202-4200

 1-888-ASK-USGS

 Email: infoservices@usgs.gov